David Shepherd and Travis Price, two very cool guys whose names should be household words as avatars of compassion, saw a new kid at their Nova Scotia High school get bullied on his first day of school in 2007 — for daring to wear a pink polo shirt. David and Travis went right out and bought every pink shirt they could find and persuaded other kids in their school to wear one in solidarity with the victim — and to mock the bullies.

If only every person who sees someone being bullied mustered the bravery to do something equally loving and supportive. How different, and better, our world would be!

This year an estimated 13 million children will be bullied in the United States.

(That’s three times the population of Ireland. Nice.)

Pink Shirt Day — Feb. 29 — is now a national, powerful, highly visible movement in my native Canada, and a clear way to show support for, and solidarity with, those whose lives are being made a living hell by the weak and cowardly wretches who taunt them.

I was bullied mercilessly in my middle-class Toronto high school for three years. I’d arrived, halfway through Grade 10, to a cliquish place where everyone had attended the same elementary and middle schools together. A trio of boys decided to make me the object of their daily derision.

Their tactics included putting a dog biscuit on my desk, barking at me and shouting “Doglin!” down those echoing hallways. I cried (never publicly), over-ate, shouted back, felt ugly for many years afterward.

No one in authority at my school — fully aware of this behavior and its effects on me — did a thing.

I wrote about this for USA Today, an essay that still draws reaction. A few months ago, a total stranger living upstate from me in a small town called me out of the blue — to ask my advice for her young son, being bullied by a young girl (!) whose parents (of course) hold positions of authority and who knew she could keep getting away with it.

They are suing their school officials and their son has watched these adults line up to lie and cover their taxpayer-paid asses. Talk about an education.

I don’t have kids, but I do know what it feels like to be singled out for abuse, to have adults turn a blind eye, to have fellow students snicker in voyeuristic pleasure — sighing with relief it isn’t them.

Lee Hirsch, another former bullying victim, has made a new documentary, Bully, in theatres March 30. I applaud his commitment to making this film and everyone associated with it.

In a series of recent experiments, a group of psychologists at the University of California, Los Angeles, recorded mutual dislike among 2,003 middle school students. Unlike previous studies on the same topic, these researchers also compared children who reciprocated a fellow classmate’s dislike with those who did not. Students who were not named at all on anyone’s blacklist were excluded from this analysis.

This comparison found that the girls who returned classmates’ hostility scored significantly higher on peers’ and teachers’ ratings of social competence. They were more popular and widely admired. The boys who did the same scored highly on teachers’ ratings of classroom behavior.

“You have several options, as I see it, when you become aware of someone else’s antipathy,” said Melissa Witkow, now at Willamette University in Oregon, the psychologist who led the study. “You could be extra nice, and that might be good. But it could also be awkward or disappointing, and a waste of time. You could choose to ignore the person. Or you can engage.”

She said the study suggested that “when someone dislikes you, it may be adaptive to dislike them back.”

I’ve blogged here about being bullied and how traumatic that was for me. But being disliked — which happens to all of us — is different from being bullied.

I was sent off to boarding school at eight and summer camp at the same age. An only child, I wasn’t used to being teased or fighting with siblings, so running into haters was a new experience. And, when you share a room for many months with four or six other girls — one or more of whom are nasty — you’ve got nowhere to run or hide. The closet? The bathroom?

I still remember a blonde girl named Stephanie and a dark-haired Kathy who were mean. Mean! But it was sort of fun to throw their energy right back at them. It’s not pleasant to discover not everyone likes you, but if they did, you’d probably be way too accommodating. Whenever Stephanie started sharpening her tongue, I was ready with a retort. I actually bit Kathy’s finger once, hard, when she was stupid enough to stick in my face and dare me to. She didn’t make that mistake twice.

Fighting for yourself — when not against a team of relentlessly toxic bullies — is a useful skill. Girls are too often taught to “be nice” when being tough, smart and ready and willing to defend yourself, verbally or even physically, is a better option. Like knowing how to cook or clean or change a tire, it’s a useful life skill.